﻿using System;
using System.Collections.Generic;
using System.Linq;

/* Copyright (c) 2010 CBaxter
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 
 * IN THE SOFTWARE. 
 */

namespace Xpedite.Resources.Compressors
{
  internal class AcceptEncodingHeader
  {
    private readonly String _header;
    private readonly IDictionary<String, AcceptEncoding> _acceptEncodings;

    public String Header { get { return _header; } }
    public IEnumerable<AcceptEncoding> Codings { get { return _acceptEncodings.Select(item => item.Value); } }

    public AcceptEncodingHeader(String header, IDictionary<String, AcceptEncoding> acceptEncodings)
    {
      Verify.NotNull(header, "header");
      Verify.NotNull(acceptEncodings, "acceptEncodings");

      _header = header;
      _acceptEncodings = acceptEncodings;
    }

    public Single GetAcceptEncodingQualityFor(String coding)
    {
      Verify.NotNull(coding, "coding");

      AcceptEncoding acceptEncoding;
      if (_acceptEncodings.TryGetValue(coding.ToLowerInvariant(), out acceptEncoding))
        return acceptEncoding.Q;

      return _acceptEncodings.TryGetValue("*", out acceptEncoding) ? acceptEncoding.Q : 0F;
    }

    public static AcceptEncodingHeader Parse(String header)
    {
      Verify.NotNull(header, "header");

      IDictionary<String, AcceptEncoding> parsedHeader = header.Split(',')
                                                               .Where(item => !String.IsNullOrEmpty((item ?? String.Empty).Trim()))
                                                               .Select(item => AcceptEncoding.Parse(item))
                                                               .ToDictionary(item => item.Coding.ToLowerInvariant());

      return new AcceptEncodingHeader(header, parsedHeader);
    }
  }
}
